This invention relates generally to batteries, and relates more particularly, to the structure and methods of construction of rechargeable lithium batteries.
Heretofore, the life and performance of lithium batteries have been limited by two major factors. The first of such factors relates to the occurrence of a chemical reaction between the liquid organic or polymer electrolyte and the lithium anode so that a resistive film barrier forms upon the anode. This film barrier increases the internal resistance of the battery and lowers the amount of current capable of being supplied by the battery at the rated voltage.
The second of such factors relates to the undesirable consequences which can result from repeated cycling of the battery. More specifically, battery cycling is at least partly responsible for the dendritic growth of Li on the anode and the formation of a passivating powder-like substance commonly referred to as "dead" lithium at the surface of the lithium anode, either of which can adversely affect the efficiency of the battery. In addition to reducing efficiency, the Li dendrites may grow large enough to touch the cathode through the electrolyte and thereby short the battery.
It is an object of the present invention to provide a new and improved lithium battery structure which circumvents the aforedescribed limitations and an associated method of making the battery.
Another object of the present invention is to provide such a battery having a structure which reduces the likelihood of the occurrence of an undesirable chemical reaction between the electrolyte and the lithium anode of the battery.
Still another object of the present invention is to provide such a battery having a structure which prevents the formation of Li dendrites or passivating "dead" lithium at the anode surface.